cjson: security bump to version v1.2.1

Fixes a potential NULL pointer dereference in
cJSONUtils_InplaceDecodePointerString():

https://github.com/DaveGamble/cJSON/issues/96

[Peter: extend commit message, mention (potential) security impact]
Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/cjson/cjson.hash

@@ -1,2 +1,2 @@
 # Locally computed:
-sha256 df549298ea6515058648eaacc62bcc4f82fa34f8b93af7753e30eb35c3841c7d  cjson-v1.2.0.tar.gz
+sha256 1d976ca423d714b7e836cfbc1980b56f49962d0dfe654edb3c2ffa5c713af242  cjson-v1.2.1.tar.gz

package/cjson/cjson.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-CJSON_VERSION = v1.2.0
+CJSON_VERSION = v1.2.1
 CJSON_SITE = $(call github,DaveGamble,cjson,$(CJSON_VERSION))
 CJSON_INSTALL_STAGING = YES
 CJSON_LICENSE = MIT